Pneumatic tire.



PATENTED MAR. 24-; 1908.

- E. A. MARSIL "PNEUMATIC TIRE. APPLIOATIOIL rum) NOV. 7, 190a.

Cll xrencakfla y. .774 5 M ELON A. MARSH, OF DETROIT, MICHIGAN.

PNEUMATIC TIRE.

Application filed. November 7, 3.906.

Specification of Letters Patent.

Patented Mme 24, 1908.

fleriel sesssi.

To all whom it may concern; 1,

Be it known that l, Eros A. llllmsiu, e. oiti- Zen of the United Stet-es, residing at Detroit, count of Weyne, State of ltlichi un, have invented a certain new and .useful lmprovement in Pneumatic Tires, and declare the following to be e full, clear, and exact description of the sums, such as will enable oth, ers skilled in'the art to which it pertains to rnske end use the some, reference being bed to the accompanying drawings, which form pert o'ithis specification,

This inventioureletes to pneumatic tires; it has ior'its object on improved tire intended and adapted to prevent puncture by the sot-ion of any object or article which may pierce the outer covering of the tire, and press against the inner tube in which the air of the pneumatic cushion is contained, and

I this Objfit is attained by e form of construe tion that is entirely in, the muteriel of which the tube is mede end Without guards or sheaths of up extreneous materiel.

T he put theistic tire which has come most extensively into use is one in which the inner tube of comparatively soft, flexible end elustic materiel that is impervious to sir is contained in, and guarded by outer tube that is flexible and elsstic, and is adapted to Withstand the ubrediug action resulting from the ordinary movements of e' Wheel along the earth. The two together form the boost socepteble cushion device thst modern iencc hes. applied to vehicle Wheels. in this construction, the outer tube, from will, nature of the materiel from Wiilfill it is constructed, s liable to be pierced or out through by any sharp srticle over which the wheel may roll; end theinner tube being strained by the air contained therein is also liable to be punctured by the sharp point of the same article,

lit is e WP-ll knows ct thet indie rubber, the materiel of whi h the tube v :cted, especially the soft, pliable, fie 7 highly elasticrubber of the inner tube eiiords u considerable resistance to even s sharp pointed article, and will stretch greatly before e share pointed article will uncture it, nevertheless, the limit to which 1t will stretch is reached long before the surface against Which the sherppointpresses, 1s forced over against the opposite side of the tube; the air under pressure in the tube tends to prevent the wells oi the air containing tube from u puncture takes place.

Q I I a I in the device in which this invention isrielding sufficiently, and the embodied, that part of the inner tube which is most liable to puncture is made in folds, and these folds are constructed to furnishsmple material to yield before the end of a pointed article pressing a ainst the tube from the outside, and shou d the pointed article by any chence'pu'ncture the tube through one of these folds, the sir pressing against the mass of folds tends to compress the rubber edge- Wise around the opening of the puncture in stead of to expand it, and the puncture is thus self closing, and the edges of'the hole are so held together that the air does not escape freely from Within the contained tube, and" unless the uncture be Very large, will not escape et a and at all times the resence oi other folds on each side of eac efi'ects their support in erect radial position.

in the rlrawings1-Figure 1, is a side elevation oi it part of the inner tube, the outer tube being shown in section, and one part of the inner tube being shown in elevation, and one part in section. Fig. 2, is a cross section. Fig- 3, is a diagram indicating the action of v e puncturing article against the inner tube now in use. Fig. 4, is a diagram showing the action of an article puncturing the outer tube end pressing against the folds of the inner tube i Prelereblv the inn-er tube should be made to fill withbut being ut under any great tension, the chamber, oi the outer tube; generally it is in ride both smaller in diameter and shorter in length, and is exp ended by internel assure inst the wells of the outer tube.

in the drawings, A indicates the outer tube which serves to hold the inner tube'in should be so deep in extent along a radius of the tube thet an object pressing against the tube will force the corrugations to unfold before it begins to stretch the materiel. The inner rim 1) of this air containing tube is preferably made uncorrugeted and in the ordinary form; the corrugat ons they extend.

- pressmg entirely around, but it is a needless extravagance 1n the use of the rubber and an objectionable addition to the Weight of the completed tire to continue the corrugations over a surface that is not liable to be attacked by a puncturing article, and it is sufficient if the corrugations extend to each side of the lower part of the tread for at most half of the distance around the inner tube. They should extend so far that any article pressing against the surface of the inner tube any where along the tread half of the tube will open out the folds and furnish a sufficient quantity of material in front of the inarticle without straining and stretching the rubber to, or nearly 'to', its elastic limit.

I have found ex erimentally that a sheet of rubber punctured in a stretched or strained condition, whether the strain be much or little, increases the size of the puncture and the aperture is lar er than the instrument which made it, on t e contraryfif a sheet of rubber be compressed edgewise, a puncture existing therein closes up, and it is this law which I have taken advantage of and have formed theiubber of which the inner tube is made with-folds that are in a osition and relation such that they tend to t icken under the pressure of the air which is contained in the tube. The folds thus formed and arranged may be considered as truss constructions in which the mass of material serves as strut or compression members and the edges or bends of the folds serve as tie members; generally with this construction the tube will yield, instead of being punctured. Should, however, it be punctured by any accident, the pressure of the contained air tends to force the folds outward, and these being resisted by the outer tube, the pressure compresses the rubber edge-Wise instead of expanding it, and any out or puncture through the rubber at this point is. auto? matically closed rather than opened, and especially should there be a tear in the outer tu e, the pressure of the inner tube tending to force the folds or rubber into and possibly through the tear, will compress them strongly against one another.

In the diagram shown in Figs. 3 and 4, is represented the action of an article puncturing the outer tire A, and pressing against the inner tire. In case the mner tire be uncorrugated, the point of the in-pressin article forces the rubber in front of it and t 1e pressure of the air which is contained within the sack holds the rubber quite closely to, or quite near to the article which is pressing against the rubber, and therubber at the points e held against the outer covering A, by the pressure of the included air, are under tension by a force equal to that of the pressure of the air contained in the tube. The rubber under these circumstances can 'eld before the point of the article P until its elastic limit is reached and then the article P passes through the rubber. When, however, the corrugated tube in which this invention is embodied is acted upon by a puncturing article P,'the folds a furnish material which may yield and unfold before the point of the puncturing article P and the elastic limit of have unfolded. The internal pressure is just as great,'but the construction enables the rubber will not be reached until the folds the material to yield, and the internal pressure even aids the unfolding when the article assumes the shape shown in Fig. 4, by tending to press the inner angle If outward, and while it holds the material 0 ose against the puncturing article, it does not strain it.

What I claim is p In a pneumatic tire, in combination with an outer covering, an inner tube adapted to contain air provided with truss-shaped folds extending in close relation, transversely of and partly around the tread side of said inner tube, whereby provision is made for. retaining the folds in proper position for yielding before a puncturing article and for pressthe edges of a puncture in one of said 1n fo ds against each other, described.

In testimony whereof, I, sign this specification in the presence of two witnesses.

ELON A. MARSH.

substantially as Witnesses:

CHARLES F. BURTON, MAY E. Kor'r. 

